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Direct observations from the geologic record are commonly used in conjunction with indirect seismic inferences to detail environmental settings and stratal architecture of sedimentary successions. However, examples of integration between seismic and macrobenthic insights are scarce and limited to the use of such a group as an auxiliary to other proxies. We investigated mollusc and ostracod assemblages along an onshore-offshore transect that intersects the C-2 clinothem (15.6 - 14.4 ka BP) and the overlying transgressive deposits that recorded the last phase of progradation and abandonment of the Po River Lowstand Wedge (PRLW). We applied multivariate analyses to benthic data to assess the extent to which mollusc and ostracod assemblages can improve both the resolution of seismic-derived depositional environments and the sequence stratigraphic architecture of targeted sedimentary succession. Along the onshore-offshore transect, seismic reflection geometries correspond with three broad sedimentary environments: High Amplitude Continuous reflections (HAC) are interpreted as delta plain/subaqueous shelves, High Amplitude Continuous Wavy Dipping reflections (HACWDip) as prodeltas and Low Amplitude Continuous reflections (LAC) are associated to distal basin settings. The integration of quantitative palaeoecologic trends with seismic-derived depositional environments allowed us to subdivide the HAC facies into a proximal (core LSD-26) and distal (cores LSD-27 and -28) area. The proximal HAC facies, in particular, encompasses lower delta plain semi-barred settings with vegetated substrates that upcore pass to nearshore settings. The distal HAC facies is distinguished by clusters that suggest ecological mixing due to strong bioturbation and wave-aided hyperpycnal flows in offshore transition/inner shelf settings. The paucity of benthic fauna for the geophysical units HACWDip (core LSD-05) and LAC (core LSD-04) hampered a complete reconstruction of the palaeoenvironmental dynamics. However, both benthic groups support a seismically derived interpretation of shelf and basinal settings, respectively, and both were subjected to high sedimentation rates. Moreover, integration of mollusc and ostracod multivariate-derived trends with grain-size data across the onshore-offshore transect reveals distinctive stratal stacking patterns that are useful in constraining the position of the Maximum Regressive Surface that marks the abandonment of the PRLW in the Central Adriatic Sea.

Collection of abstracts of the Paleodays 2021 Bologna (14)15-17 June 2021 held in Bologna, Italy

The 10Be/9Be ratio is commonly employed as a tool for establishing the stratigraphic position of paleomagnetic excursions and reversals whenever the traditional paleomagnetic approach fails to provide conclusive results. In particular, it is held that 10Be production rates in the atmosphere depend on the strength of the Earth’s magnetic field, and the fallout and deposition of cosmogenic beryllium at the surface happen on a very short time scale. However, investigations performed on terrestrial and marine successions demonstrate that the 10Be record and the paleomagnetic signal are often asynchronous. Mechanisms that control the conveyance and deposition of cosmogenic 10Be to the seafloor are still ambiguous and poorly documented. Here, we discuss the dynamics of 10Be in a central Mediterranean marginal marine depositional scenario characterized by a pervasive terrigenous influx. Our data show that a very close correlation exists between 10Be concentrations and the local proxy of rainfall rates and regimes (pollen), indicating that a considerable 10Be transport from the mainland may occur in response to the remobilization of terrestrial reservoirs during periods of increased runoff. Superimposed is a dynamic oceanographic setting that further controls the preservation potential of 10Be at the bottom, in terms of changing water chemistry and/or composition of the sedimentary flux to the seafloor. Results of our investigation suggest that, in particular environmental and depositional settings, the interplay between climate, terrigenous yield and oceanography may jeopardize the sedimentary depiction of the meteoric 10Be contribution, thus challenging the use of 10Be for tracking the stratigraphic position of geomagnetic reversals.

Le previsioni di un incremento delle temperature globali e di un conseguente innalzamento del livello del mare nei prossimi decenni/secoli ha sollevato interrogativi riguardo la risposta dei parassiti al cambiamento climatico antropogenico. In particolare questo lavoro prevede lo studio delle tracce di parassitismo da trematodi digenei Gymnophallidae che si manifestano in forma di pits, depressioni ovali con bordi rialzati all’interno delle valve di esemplari fossili di Abra segmentum, per verificare se questo tipo di lesione sia presente (e con quale frequenza) anche negli esemplari attuali comparandole con quelle evidenziabili in A. segmentum datati fino a circa 9000 anni fa. Gli esemplari viventi di A. segmentum studiati in questa ricerca sono stati campionati in tre aree salmastre costiere, Piallassa Baiona (RA), Saline di Cervia (FC) e Laguna di Lesina (FG). Le località scelte rappresentano habitat ideali per la specie A. segmentum, nonché analoghi moderni degli ambienti olocenici in studio. Per ogni sito sono state delimitate aree di 25 m2 e, per i siti romagnoli, raccolti ~200 esemplari vivi di A. segmentum durante Giugno - Luglio 2017, mentre nella Laguna di Lesina oltre ai campionamenti estivi consistenti in ~200 esemplari vivi, erano stati prelevati ulteriori ~100 esemplari anche durante Novembre - Dicembre 2016. I bivalvi sono stati aperti ed esaminati allo stereomicroscopio; il tessuto molle è stato rimosso dalle valve e pressato tra due vetrini portaoggetto per l’individuazione di sporocisti, cercarie e metacercarie di trematodi digenei, con particolare attenzione a queste ultime che sono ritenute responsabili della formazione dei pits sulle valve interne (Campbell, 1985, Cremonte & Ituarte, 2003). Gli elementi parassitari riscontrati venivano fissati in etanolo 70%, sia previo isolamento sia all’interno dei tessuti, per la successiva identificazione morfologica e molecolare. I risultati indicano valori di prevalenza di stadi larvali di trematodi digenei molto variabili e talvolta molto elevati nella Laguna di Lesina (tra 6 e 61%), e valori di prevalenza inferiori e con range meno ampio in quelli delle Saline di Cervia (tra 23 e 34%) e Piallassa Baiona (tra 7 e 17%). Quando riferiti agli esemplari con sole metacercarie la prevalenza media nella laguna di Lesina scende al 21%±5%, 20%±5% per le Saline di Cervia e 7%±3% per Piallassa Baiona. A livello stagionale, nella Laguna di Lesina i campioni invernali hanno presentato prevalenza inferiore rispetto a quelli estivi, con valore massimo di 6%. L’analisi dei pits sulle valve degli esemplari attuali parassitati ha messo in luce come gli esemplari di A. segmentum viventi sviluppino accenni di pits molto meno marcati rispetto alle controparti fossili, sebbene sia da evidenziare come l’identificazione dei parassiti reperiti nel corso della presente indagine sia ancora in corso. Il confronto preliminare tra i valori di prevalenza dei pits in A. segmentum fossili riportati da Scarponi et al. (2017) evidenzia come mediamente la presenza dei pits nel record fossile durante le fasi di rapido innalzamento del livello marino appaia più elevata rispetto agli esemplari attuali. I risultati ottenuti nel corso di questa indagine nel confronto tra Abra segmentum fossili e attuali, pone l’accento sull’importanza di ulteriori approfondimenti sul rischio che l’aumento del livello marino causato dal riscaldamento globale possa in futuro, come già accaduto in passato, provocare una maggior diffusione e patogenicità di parassiti marini con effetti negativi sugli ecosistemi interessati.

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The direct carbonate procedure for accelerator mass spectrometry radiocarbon (AMS 14C) dating of submilligram samples of biogenic carbonate without graphitization is becoming widely used in a variety of studies. We compare the results of 153 paired direct carbonate and standard graphite 14C determinations on single specimens of an assortment of biogenic carbonates. A reduced major axis regression shows a strong relationship between direct carbonate and graphite percent Modern Carbon (pMC) values (m = 0.996; 95% CI [0.991–1.001]). An analysis of differences and a 95% confidence interval on pMC values reveals that there is no significant difference between direct carbonate and graphite pMC values for 76% of analyzed specimens, although variation in direct carbonate pMC is underestimated. The difference between the two methods is typically within 2 pMC, with 61% of direct carbonate pMC measurements being higher than their paired graphite counterpart. Of the 36 specimens that did yield significant differences, all but three missed the 95% significance threshold by 1.2 pMC or less. These results show that direct carbonate 14C dating of biogenic carbonates is a cost-effective and efficient complement to standard graphite 14C dating.

The Arda River marine succession, cropping out in western Emilia (northern Italy) represents an excellent site to study past ecosystems dynamics in the frame of Early Pleistocene climate change and tectonic activity. This one-day excursion leads the participants to discover the palaeoclimatic and palaeoenvironmental evolution of the Lower Pleistocene Arda River marine section, unraveled through an integrated use of sedimentological, palaeoecological (molluscs and trace fossils) and geochemical tools. Upsection, the succession was deposited in progressively shallower water and colder climate during phases of advance of fan deltas affected by hyperpycnal flows. It culminates at the top with clast supported alluvial conglomerates and freshwater/terrestrial biota indicating a sea level drop and the establishment of a continental environment. It is very rich in fossils: in the marine part molluscs, brachiopods, corals and echinoderms, besides well preserved trace fossils, are abundant; whereas in the continental part a mammal fauna and freshwater/terrestrial molluscs are occasionally found. Sclerochemical analyses undertaken on bivalve shells indicate that seawater temperature seasonality was the main variable of climate change within the study area during the Early Pleistocene. In particular, strong seasonality and low winter palaeotemperatures were assumed to be the main drivers for the widespread establishment of Arctica islandica populations in the palaeo-Adriatic Sea around 1.80 Ma. During the excursion not only fossils are shown, but also interesting biocalcarenitic bodies with a complex geometry cropping out in the town of Castell’Arquato. The excursion is complemented by the visit to the Giuseppe Cortesi geological and palaeontological museum, housing vertebrate and invertebrate fossil collections.

[The Po River Lowstand Wedge (PRLW) of the central Adriatic Sea is made up of stacked alternated clinothems (Type A, B and C clinothems) that show different amount of aggradation of their topsets (e.g. Pellegrini et al., 2018). In this paper, we present novel sedimentological and paleontological analyses and discuss the processes responsible for the observed successions. We detail the character of the clinoforms deposited at the shelf‐edge, discussing the importance of hyperpycnal and storm‐enhanced sediment‐gravity flows in controlling the lithologic assemblage of the different tracts of the compound clinoforms. More in general, we show that, when the fine details of prograding clinoform units are investigated, the processes that lead to margin outbuilding are more complex than usually envisaged. , Abstract Clinoforms with a range of scales are essential elements of prograding continental margins. Different types of clinoforms develop during margin growth, depending on combined changes in relative sea level, sediment supply and oceanographic processes. In studies of continental margin stratigraphy, trajectories of clinoform ‘rollover’ points are often used as proxies for relative sea‐level variation and as predictors of the character of deposits beyond the shelf‐break. The analysis of clinoform dynamics and rollover trajectory often suffers from the low resolution of geophysical data, the small scale of outcrops with respect to the dimensions of clinoform packages and low chronostratigraphic resolution. Here, through high‐resolution seismic reflection data and sediment cores, we show how compound clinoforms were the most common architectural style of margin progradation of the late Pleistocene lowstand in the Adriatic Sea. During compound clinoform development, the shoreline was located landward of the shelf‐break. It comprised a wave‐dominated delta to the west and a barrier and back‐barrier depositional system in the central and eastern area. Storm‐enhanced hyperpycnal flows were responsible for the deposition of a sandy lobe in the river mouth, whereas a heterolithic succession formed elsewhere on the shelf. The storm‐enhanced hyperpycnal flows built an apron of sand on the slope that interrupted an otherwise homogeneous progradational mudbelt. Locally, the late lowstand compound clinoforms have a flat to falling shelf‐break trajectory. However, the main phase of shelf‐break bypass and basin deposition coincides with a younger steeply rising shelf‐break trajectory. We interpret divergence from standard models, linking shelf‐break trajectory to deep‐sea sand deposition, as resulting from a great efficiency of oceanographic processes in reworking sediment in the shelf, and from a high sediment supply. The slope foresets had a large progradational attitude during the late lowstand sea‐level rise, showing that oceanographic processes can inhibit coastal systems to reach the shelf‐edge. In general, our study suggests that where the shoreline does not coincide with the shelf‐break, trajectory analysis can lead to inaccurate reconstruction of the depositional history of a margin.]

Variations in the isotopic composition of sulfur in sedimentary pyrite (δ34Spyr) are often used to reconstruct global sulfur biogeochemical cycling and Earth's surface oxidation state over Earth history. Recent work, however, has shown that δ34Spyr is strongly impacted by local depositional conditions, which both confounds attempts to reconstruct global sulfur cycling and provides a new proxy for investigating local paleoenvironmental conditions. We present a chemostratigraphic record of δ34Spyr in a detailed paleoenvironmental and sequence stratigraphic framework spanning the Early-Mid Pleistocene transition from the Crotone Basin (Calabria, Southern Italy). Bulk δ34Spyr data parallel transgressive-regressive cycles and enable the differentiation of progradational and retrogradational stacking patterns, where δ34Spyr values decrease toward −50‰ in outer shelf deposits during late transgression and become more positive and variable in prograding sedimentary units accumulated in shallower environments. In parallel with the observed variations in δ34Spyr, complementary data on organic carbon abundance and isotopic composition and total nitrogen abundance document changes in terrestrial delivery of sediment to the basin, as a consequence of glacial-interglacial eustatic sea-level changes, regional climate and local tectonics. The chemostratigraphic record of δ34Spyr appears sensitive to variations in sedimentation rates and local erosional surfaces and therefore may represent a powerful tool to assess stratal stacking patterns for sequence stratigraphic interpretations of siliciclastic successions. These results highlight the role of local conditions in controlling sedimentary δ34Spyr records and illustrate how isotopic data can be used to reconstruct key parameters of the sedimentary environment that might not otherwise be accessible, especially in deep-time strata.

In the field of medical care, successful transition from pediatric-centered to adult-oriented healthcare can provide a sense of continuity in the development of youth, and prepare them to accept responsibility for and manage their own chronic kidney condition in complete autonomy. The so-called transition process requires the presence of some basic aspects: a multidisciplinary team, which acts as a bridge between child and adult services; a comprehensive clinical, cognitive, psychological, and social change for the young people; the involvement of family and caregivers. Within the framework of transition and chronicity during the developmental age, we selected international papers explaining models which agreed on some important steps in the transition process, although many differences can be observed between different countries. In fact, in Europe, the situation appears to be heterogeneous as regards certain aspects: the written transition plan, the educational programmes, the timing of transfer to adult services, the presence of a transition coordinator, a dedicated off-site transition clinic. We then analyzed some studies focusing on patients with renal diseases, including the first to contain a standardized protocol for transition which was launched recently in the USA, and which seems to have already achieved important positive, although limited, results. In Italy, the issue of transition is still in its infancy, however important efforts in the management of chronic kidney disease have already been initiated in some regions, including Emila Romagna, which gives us hope for the future of many young people.

Growing evidence suggests that biodiversity mediates parasite prevalence. We have compiled the first global database on occurrences and prevalence of marine parasitism throughout the Phanerozoic and assess the relationship with biodiversity to test if there is support for amplification or dilution of parasitism at the macroevolutionary scale. Median prevalence values by era are 5% for the Paleozoic, 4% for the Mesozoic, and a significant increase to 10% for the Cenozoic. We calculated period-level shareholder quorum sub-sampled (SQS) estimates of mean sampled diversity, three-timer (3T) origination rates, and 3T extinction rates for the most abundant host clades in the Paleobiology Database to compare to both occurrences of parasitism and the more informative parasite prevalence values. Generalized linear models (GLMs) of parasite occurrences and SQS diversity measures support both the amplification (all taxa pooled, crinoids and blastoids, and molluscs) and dilution hypotheses (arthropods, cnidarians, and bivalves). GLMs of prevalence and SQS diversity measures support the amplification hypothesis (all taxa pooled and molluscs). Though likely scale-dependent, parasitism has increased through the Phanerozoic and clear patterns primarily support the amplification of parasitism with biodiversity in the history of life.This article is part of the theme issue ‘Infectious disease macroecology: parasite diversity and dynamics across the globe’.

The Arda and Stirone marine successions (Italy) represent key sections for the early Pleistocene; they were deposited continuously within a frame of climate change, recording the Calabrian cooling as testified by the occurrence of the “northern guests,” such as the bivalve Arctica islandica. In addition, although the first occurrence of A. islandica in the Mediterranean Sea was used as the main criterion to mark the former Pliocene-Pleistocene boundary, the age of this bioevent was never well constrained. Here, we describe the Stirone depositional environment and constrain for the first time the section age using calcareous nannofossil and foraminifera biostratigraphy. We also correlate the Arda and Stirone sections using complementary biostratigraphic and magnetostratigraphic data. Our results indicate that A. islandica first occurred in both the successions slightly below the top of the CNPL7 biozone (dated at 1.71 Ma). Comparisons with other lower Pleistocene Mediterranean marine successions indicate that the stratigraphically lowest level where A. islandica first occurred in the Mediterranean Sea is in the Arda and Stirone sections; these environments satisfied the ecological requirements for the establishment and the proliferation of the species, which only subsequently (late Calabrian) has been retrieved in southern Italy and other areas of the Mediterranean Sea.

Le alghe calcaree sono importanti organismi calcificanti biocostruttori di fondi mobili (rodoliti) e duri diffuse in tutto il Cenozoico. Tra le rodoliti, il morfotipo a rami liberi (maerl) è presente sia in Atlantico che in Mediterraneo. Lithothamnion corallioides è una delle specie più abbondanti e diffuse nel maerl, tra 28°N e 58°N (Irvine and Chamberlain, 1994). Essa forma strutture ramificate, di colore da marrone a viola, spesso sterili, con diametro dei rami compreso tra 1-2 mm, e con apice a forma di pomello (Irvine and Chamberlain, 1994). In sezione longitudinale, i rami di L. corallioides mostrano un’alternanza di bande più chiare, legate allo sviluppo di cellule più allungate, e bande più scure, caratterizzate da cellule più tozze. Il banding è stato interpretato come la risposta della crescita variabile stagionale (Halfar et al., 2000), ma anche come l’alternanza tra cellule con ultrastrutture mineralizzate della parete differenti (Nash et al. 2019). Le pareti cellulari mostrano solitamente uno strato esterno con calcite aciculare tangenziale al plasmalemma, e uno più interno con calcite aciculare radiale (Giraud and Cabioch, 1976). La forma dei cristalli è stata interpretata come espressione fenotipica del genotipo, con risultati incoraggianti a livello di famiglia (Auer and Piller, 2020). Per valutare se le ultrastrutture subiscono modificazioni morfologiche nei diversi ambienti di vita della specie e a tassi di crescita diversi, sono stati studiati sei campioni di L. corallioides provenienti dall’Oceano Atlantico e dal Mar Mediterraneo da profondità variabili (12-66 m). A livello macroscopico, i campioni sono tutti morfotipi a ramo di colore bianco-rosa-lilla, lunghezza massima di 3 cm e diametro inferiore a 2,5 mm. Il campione di Morlaix (Francia, 12 m), dove studi genetici sulla biodiversità algale hanno escluso altre specie dello stesso genere (Carro et al. 2014), è stato identificato come L. corallioides. Su questo campione sono stati definiti gli elementi ultrastrutturali della parete cellulare, caratterizzata da un doppio strato: la parete primaria, più esterna, con cristalli di forma rettangolare molto allungati e appiattiti, simili ad aciculi tangenziali in sezione longitudinale; la parete secondaria, più interna, costituita da cristalli con forma di mattoncini tozzi e dai bordi arrotondati, solo apparentemente allungati e radiali al plasmalemma in sezione longitudinale. Sia il peritallo che l’epitallo mostra cellule con calcificazione primaria e secondaria con le stesse caratteristiche morfologiche. Il confronto degli altri campioni con questo, basandosi anche sulle ultrastrutture, ha permesso di identificarli come L. coralllioides. Sebbene siano vissuti in ambienti molto diversi e abbiamo un tasso di crescita differente (Piazza et al., under review), le ultrastrutture della parete non subiscono deformazioni, il che permette di sostenere che il processo di mineralizzazione nelle coralline sia biologicamente controllato.

Rapid warming and sea-level rise are predicted to be major driving forces in shaping coastal ecosystems and their services in the next century. Though forecasts of the multiple and complex effects of temperature and sea-level rise on ecological interactions suggest negative impacts on parasite diversity, the effect of long term climate change on parasite dynamics is complex and unresolved. Digenean trematodes are complex life cycle parasites that can induce characteristic traces on their bivalve hosts and hold potential to infer parasite host-dynamics through time and space. Previous work has demonstrated a consistent association between sea level rise and increasing prevalence of trematode traces, but a number of fundamental questions remain unanswered about this paleoecological proxy. Here we examine the relationships of host size, shape, and functional morphology with parasite prevalence and abundance, how parasites are distributed across hosts, and how all of these relationships vary through time, using the bivalve Chamelea gallina from a Holocene shallow marine succession in the Po coastal plain. Trematode prevalence increased and decreased in association with the transition from a wave-influenced estuarine system to a wave-dominated deltaic setting. Prevalence and abundance of trematode pits are associated with large host body size, reflecting ontogenetic accumulation of parasites, but temporal trends in median host size do not explain prevalence trends. Ongoing work will test the roles of temperature, salinity, and nutrient availability on trematode parasitism. Parasitized bivalves in one sample were shallower burrowers than their non-parasitized counterparts, suggesting that hosts of trematodes can be more susceptible to their predators, though the effect is ephemeral. Like in living parasite-host systems, trematode-induced malformations are strongly aggregated among hosts, wherein most host individuals harbor very few parasites while a few hosts have many. We interpret trace aggregation to support the assumption that traces are a reliable proxy for trematode parasitism in the fossil record.